Never occurred to me, but it sounds like a good way to get yourself violently ill. (Relative had very bad experience getting inked.) But if you feel you absolutely must, one of the more tasteful options imo would seem to be getting one of the "hockeyist" pose, on your scapula (the back of your shoulder). Whatever you choose, have it done as a henna painting first, to see if you like whatever design in this or that particular place.